Starting system for two-cycle gas engines



April 17, 1956 INVENTOR BY Ma a/WM UnitedStates Patent A ice 2,742,380 vsran rrncsirsrnrm on rwo cvcnn GAS :nnenvns Byron M. Peters, Lathrop, Calif.

Application Augus't'30, "1954,-'Serial No. 452,819

Claims. (Cl. 123 182) l his invention relates to twocycle gas engines, and particularly to small one-cylinder engines of this type which-"because of the added weight, cost, *and other factors- -are not equipped with self-starters.

Such 'Iengin'es take and compress the fuelmixture into the cylinder with each revolution of the crankshaft, and this feature sometimes makes it hard to start the engine, especially when a disadvantageous manually actuated leverage device must be used to turn the engine and against the repeated resistance of compression.

It is therefore the major object of my invention to provide a system to facilitate the starting of a two-cycle gas engine by relieving the compression in the cylinder without dissipating the mixture into the air adjacent the engine, and where the volatile mixture might catch fire.

A further object of the invention is to provide a device for the purpose which may be readily attached to an engine without having to make any material changes thereto, or it may be incorporated in an engine during the manufacture thereof.

It is also an object of the invention to incorporate a twocycle engine, equipped with the novel starting system, in driving relation with a wheel of a tricycle-type, power driven, single-occupant vehicle, in such a manner that the engine is turned over upon advance of the vehicle along the ground by foot-work on the part of the operator, while the start-facilitating system is under the control of a hand of the operator guiding the vehicle.

Still another object of the invention is to provide a starting system which is designed for ease and economy of manufacture.

An additional object of the invention is to provide a practical, reliable, and durable starting system for twocycle gas engines, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

Fig. 1 is a somewhat diagrammatic sectional elevation of a two-cycle gas engine, showing the start-facilitating system, in the form of an attachment, mounted thereon.

Fig. 2 is an enlarged sectional elevation of the valve unit of the system, detached.

Referring now more particularly to the drawings, and to the characters of reference marked thereon, the engine here illustrated is of a conventional type and comprises a cylinder 1, a crankcase 2, a piston 3 in the cylinder, a crank 4 on the crankshaft 5, and a connecting rod 6 between the piston and crank.

An intake passage 7 opens to the crankcase when the piston reaches the top of its stroke, while an exhaust passage 8 opens to the cylinder when the piston is at or adjacent the bottom of its stroke.

A bypass passage or conduit 9 opens to the crankcase in any position of the piston and to the cylinder only when the piston is near the bottom of its stroke.

2,742,380 Patented Apr. '17, 1956 Secured in, andprojecting from, the cylinder at appoint above the top of the stroke of the piston is an elongated tubular valve housing 10; a plunger 11 having a slidingfit in :theouterend portion of the housing and projecting outwardly therefrom some distance, as shown. t

A reduced-diameter valve stem 12 projects along the housing from the inner end of the plunger, and terminates in a valve .head 13,;preferably-of the poppet type, adapted to engage a valve seat 14 in the inner end of housing 10.

A vcompression spring 15 on the plunger between the outer end of the housing and a stop washer 16 on the plunger, yieldably acts to hold the valve closed and prevents the same from being opened by reason of a tendency to vacuum within the cylinder.

A lateral passage 17 formed with the housing 10 communicates with the interior thereof at a point between the valve seat and the point of innermost movement of the plunger, and is connected to the passage 9 by a tube 18; connection between the tube and passage being'preferably made by a fitting 19 secured in the outer wall of -said passage.

In operation, as the piston 3 rises to the top of its stroke, a tendency to vacuum is set up in the crankcase, causing a flow of mixture from the intake passage 7 into the crankcase 2, and which mixture transfers into the cylinder as soon as the piston uncovers the upper end of the passage 9. Then, as the piston again rises, the transferred mixture is further compressed, setting up a resistance to a turning-over of the engine, particularly when a disadvantageous leverage must be employed to start the engine, as is the case when the engine is mounted to operate a vehicle such as that shown in my copending application for patent, Serial No. 453,005, filed August 30, 1954.

To relieve this compression, so that the engine turns over more readily, the valve 13 is opened. This allows the mixture confined in the cylinder upon the upper end of passage 9 being closed by the piston to be bypassed back into the crankcase as the piston continues to rise.

The valve is thus opened by pushing in the outer exposed end of the plunger 11. This could be done by actual hand contact, but when the engine is mounted in a relatively hard-to-get-at position on a vehicle, such as that shown in the above identified copending application, the valve is opened by a hand-controlled mechanical device. Such a device includes a lever 20 pivoted intermediate its ends, as at 21, in connection with the engine, and disposed so that one end of the lever engages the outer end of the plunger 11. A housed pull-wire 22 is connected to the other end of the lever, which wire may of course extend to any convenient point of operation on the vehicle.

From the foregoing description it will be readily seen that there has been produced such a system as will substantially fulfill the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the system, still in practice such deviations therefrom may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent are desired:

1. In a two-cycle gas engine which includes a crankcase, a cylinder, a piston reciprocable in the cylinder, and a conduit between the crankcase and cylinder arranged to transfer fuel mixture from the crankcase to the cylinder only upon the piston reaching a point adjacent the bottom of its stroke; means forming a passage connecting the conduit intermediate its ends and the cylinder adjacent its outer end, and a manually operable normally closed valve in said passage means.

2. In a two-cycle gas engine which includes a crankcase, a cylinder, a piston reciprocable in the cylinder, and a conduit between the crankcase and cylinder arranged to transfer fuel mixture from the crankcase to the cylinder only upon the piston reaching apoint adjacent the bottom of its-stroke; means forming a passage connecting the com duit intermediate 1 its ends and the cylinder adjacent its outer end, and a manually opened valve normally closing the end of said passage means at its connection with the cylinder and opening into the same.

3. In a two-cycle gas engine which includes a crankcase, acylinder, a piston reciprocable in the cylinder, and a conduit between the crankcase and cylinder arranged to transfer fuelmixture from the crankcase to the cylinder only upon the piston reaching a point adjacent the bottom of its stroke; means forming a passage connecting the conduit intermediate its ends and the cylinder adjacent its outer end, a normally closed valve in said passage means,

and means to open the valve from a point relatively remote tothe engine.

4. Ina two-cycle gas engine which includes a crankcase, a cylinder, 8. piston reciprocable in the cylinder, and a conduit between the crankcase and cylinder arranged to transfer fuel mixture from the crankcase to the cylinder References Cited in the file of this patent HEDSTAI AT 1,192,515 Gibson July 25, 1916 1,290,276 Merkel Jan. 7, 1919 1,607,173 Saives Nov. 16, 1926 1,623,589 Granath Apr. 5, 1927 1,746,533 Johnson Feb. 11, 1930 2,137,482 Gil Nov. 22, 1938 2,625,924 Friedlob Jan. 20, 1953 2,648,321

Slonneger Aug. 11, 1953 

1. IN A TWO-CYCLE GAS ENGINE WHICH INCLUDES A CRANKCASE, A CYLINDER, A PISTON RECIPROCABLE IN THE CYLINDER, AND A CONDUIT BETWEEN THE CRANKCASE AND CYLINDER ARRANGED TO TRANSFER FUEL MIXTURE FROM THE CRANKCASE TO THE CYLINDER ONLY UPON THE PISTON REACHING A POINT ADJACENT THE BOTTOM OF ITS STROKE; MEANS FORMING A PASSAGE CONNECTING THE CONDUIT INTERMEDIATE ITS END AND THE CYLINDER ADJACENT ITS OUTER END, AND AMANUALLY OPERABLE NORMALLY CLOSED VALVE IN SAID PASSAGE MEANS. 